This invention relates generally to securing heat sinks to printed circuit boards.
An integrated circuit may develop sufficient heat during operation that it needs to be cooled. To this end, finned heat sinks may be secured to integrated circuits for cooling purposes. Because the heat sinks tend to be heavy, they may be mounted directly to the printed circuit board on which the integrated circuit is also mounted.
The performance of integrated circuits, such as processors, is increasing. As their performance increases, the amount of heat integrated circuits generate may increase and this may result in the need for heat sinks of increasing size. Conventionally, a heat sink is mounted on the motherboard and the enabling load is applied from the heat sink side towards the chassis in what is called “top loading.” One problem with top loading designs is that the printed circuit board may be bent downwardly by the enabling load. Excessive board deflection may be undesirable because it may result in solder joint cracking between board and board mounted components.
In a bottom loading design, the heat sink is mounted on the chassis and the enabling load is applied from below, from the chassis toward the heat sink.
One problem with bottom loading designs is that the printed circuit board may be bent upwardly by the enabling load. Excessive board deflection may be undesirable because it may result in solder joint cracking between board and board mounted components. In addition, in some designs, there may be relatively limited room between the printed circuit board and the chassis on which the printed circuit board is mounted. The bottom loading configuration must fit into whatever available space is provided.
Thus, there is a need for improved, bottom loading heat sink attachment solutions.